摘要
渤海湾盆地束鹿凹陷沙河街组三段下亚段(Es^3(下))广泛发育一套湖相混积成因"泥灰岩",是致密油勘探的主要目标层系。通过岩心和薄片观察、孔渗、压汞、扫描电镜、CT、核磁共振等分析,揭示了该套特殊成因混积泥灰岩储层地质特征;结合地质、地球化学综合分析,明确有利储层发育主控因素,建立储层分类评价标准,指出致密油勘探有利区带。结果表明:束鹿凹陷Es^3(下)泥灰岩主要包括互层混积的纹层状泥灰岩和结构混积的块状泥灰岩两类,矿物组成均以方解石为主,其次为白云石,粘土矿物与石英、长石含量低。储层孔隙度一般低于4. 0%,基质渗透率一般小于10×10^(-3)μm^2,属特低孔特低渗储层。储层孔隙类型多样、孔隙结构复杂,发育两大类8亚类储集空间,基质孔以纳米级孔隙为主。不同岩石结构的泥灰岩储层物性与孔隙结构差异明显,纹层状泥灰岩孔隙分布非均质性强,表现出双重或多重孔隙介质特征,孔渗条件和孔隙结构优于块状泥灰岩。混积泥灰岩有利储层发育受沉积亚相、岩石组构、有机质丰度与成熟度、构造缝等因素综合控制;斜坡内带及洼槽区半深湖-深湖亚相的高TOC纹层状泥灰岩是致密油勘探的有利目标。
Lacustrine marlstones of mixed silisiclastic-carbonate origin are widely developed in the lower third member of the Shahejie Formation(E s 3L)in the Shulu Sag,Bohai Bay Basin,and are the main target layers for tight oil exploration.Various data including core analysis,thin section observation,porosity and permeability measurement,mercury intrusion porosimetry,scanning electronic microscope(SEM),CT scanning and nuclear magnetic resonance(NMR)were used to clarify the geologic properties of the special marlstone reservoir of mixed silisiclastic-carbonate origin.Based on the comprehensive analyses in geology and geochemistry,the main controlling factors favorable for reservoirs development were revealed,the criteria for reservoir classification and evaluation were established,and furthermore the favorable plays for tight oil exploration were pointed out.The results indicate that the marlstones in E s 3L can be divided into two groups,namely lamellar marlstones of interlaminated mixing and blocky marlstones of structural mixing.The mineral compositions of both types are dominated by calcite,followed by dolomite,and are low in contents of clay,quartz,and feldspar.The re-servoir porosity is typically below 4.0%,and matrix permeability less than 10×10-3μm 2,manifesting its nature of ultra-low porosity and extra-low permeability reservoir.There are diverse types of reservoir pores with complicated structures,which can be divided into two categories and eight subcategories.Most of the matrix pores are nanopores.Reservoir pro-perties and pore structures are distinctly different between marlstones with diverse structures:the pore distribution in the lamellar marlstones is highly heterogeneous,featuring double or multi-porosity media;the lamellar marlstones are better than blocky marlstones in terms of porosity and pore structure.The favorable marlstone reservoirs of mixed silisiclastic-carbonate origin are controlled by sedimentary subfacies,rock fabric,abundance and maturity of organic matters,and density of structural fr
作者
付小东
吴健平
寿建峰
王小芳
周进高
张天付
郭永军
Fu Xiaodong;Wu Jianping;Shou Jianfeng;Wang Xiaofang;Zhou Jingao;Zhang Tianfu;Guo Yongjun(Hangzhou Research Institute of Geology,PetroChina,Hangzhou,Zhejiang 310023,China;;CNPC Key Laboratory of Carbonate Reservoirs,Hangzhou,Zhejiang 310023,China;North China Oilfield Company,PetroChina,Renqiu,Hebei 062552,China)
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2019年第1期78-91,共14页
Oil & Gas Geology
基金
中国石油天然气股份有限公司重大科技专项(2014E-35)
国家科技重大专项(2018A-0105)
